PB2259: MONOCYTE’S INVOLVEMENT IN INFLAMMATORY RESPONSE IN COVID-19 INFECTION IN CHRONIC RENAL DISEASE
Authors: V. Bumbea, H. Bumbea, L. Ardelean, L. Radulescu, L. Damian, I. Dumitru, C. Lambert, V. Popov, C. Tomuleasa, A.-M. Vladareanu
Journal: HemaSphere (2022)

Background: COVID-19 infection is known to associate an important inflammatory response with high risk for organ damages and thrombotic events. Monocytes are found to play an important role in inflammatory response against various antigens and are classified in three subsets: Classical, Non-classical, Intermediate. Aims: The aim of our study is to analyse monocyte subsets in patients with advanced renal failure and COVID-19 infection. Methods: We present a case-control study with paired samples: 5 patients from 15 suffering from advanced renal failure treated by hemodialysis, before, during developing a medium severity form of COVID-19 infection, and in follow-up (mean time 10 months), in which we analyzed monocytes subsets distribution and activation markers by flowcytometry from whole blood samples. Monoclonal antibodies used: CD14, CD16, CD300e, HLA-DR, CD64, CD38, CD45. Statistical analysis was performed with the Jasp and NCSS software. Results: Decreasing number of leukocytes (p=0,023), lymphocytes (p=0,029) and monocytes (p=0,167) during the infection was found, decreasing of the percentage of classical monocytes subset (p=0,295), and nonclassical monocytes subset (p=0,001), increasing in intermediate monocytes subset (p=0,115). HLA-DR and CD300e during the disease generally was increased without statistical significance (p=0,119, p=0,625), conventional monocytes had a lower CD300e (p=0,188) and HLA-DR expression is in fact unchanged with a slight tendency to increase (p=0,745), nonclassical monocytes had a higher percentage of HLA-DR (p=0,033) and CD300e (p=0,654), and intermediate monocytes had a slight elevated percentage of HLA-DR expression (p=0,332) and CD300e expression is in fact unchanged with a slight tendency to decrease (p=0,690). The percentage of classical monocytes increased (p=0,05), with a slight tendency of increasing in CD300e and HLA-DR expression after versus before infection. Nonclassical monocytes and intermediary monocytes percentage decreased after COVID-19 infection (p=0,001 respective p=0,049), but intermediary monocytes show a higher level of HLA-DR expression (p=0,012) versus before infection. CI was 95%. Boxplots in figure. Image:Summary/Conclusion: Apparently, advanced renal failure treated by hemodialysis does not dramatically change the inflammatory response medium form of COVID-19 infection. Distribution of inflammatory response consist in decreasing of percentage of classical and nonclassical monocytes, similar to severe forms of COVID-19 infection but the percentage of intermediate monocytes subset is increased. Elevation of HLA-DR and CD300e expression seems to occur especially in nonclassical monocytes, suggesting that this subset of monocytes is more activated. These changes suggest a higher inflammatory activity in nonclassical monocytes despite their lower percentage and a higher percentage of inflammatory and phagocytic intermediate monocytes. After a mean time of one year from infection resolution classical monocytes increased, and other two subtypes decreased, in nonclassical monocytes with the loss of inflammatory activity, but in intermediary monocytes with the persistence of important inflammatory activity similar during the infection, suggesting that the inflammatory response is more durable in intermediary monocytes after COVID-19 infection. The total monocytes expression of CD300e and HLA-DR after COVID-19 infection is statistically significant increase than before infection suggesting that the monocytes remain with a significant proinflammatory status after COVID infection.